Sample tube



April 1930. A. B. CUNNINGHAM 1,755,285

SAMPLE TUBE Filed Oct. 9, 19

I/vvE/vm/z;

Patented Apr. 22, 1930 UNITED STATES PATENT OFFICE ARTHUR B. CUNNINGHAM, OF CHICAGO, ILLINOIS, ASSIGNOR TO REPUBLIC FLOW METERS (30., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS SAMPLE TUBE Application filed October 9, 1922. Serial No. 593,200.

This invention relates to a device for obtaining 'samples of gas for analytical and other purposes and has for its object the provision of such a device in which the gas secured shall be free from impurities, and which shall be of simple and improved construction and convenient and eflicient in operation.

The invention is exemplified in the combination and arrangement of parts shown in the accompanying drawing and described in the following specification, and it is more particularly pointed out in the appended claims.

In the drawing, the figure is an elevation, with parts broken away, showing one embodiment of the present invention.

The numeral 1 designates a conduit, such as an ordinary gas pipe, for conducting the gas from the sample-taking tube to any desired location.

The invention is especially useful in connection with the analysis of flue gases and may be used advantageously for securing samples of such gases for CO recorders, such as that shown in my co-pending application, Serial No. 501,077. The sample tube itself is placed in the flue or smokestack of a power plane and the pipe 1 leads from the tube to the CO recorder. It will be apparent, of course, that the device may be placed in any other position from which it is desirable to secure samples of the surrounding gas.

A casing 2 of reticulated material, such as a section of sheet metal pipe perforated by openings 3 forms the shell or foundation for the sample tube. The casing 2 is closed at one end by an imperforateplate 4 which may be welded or otherwise secured to the end of the tube2. A suitable closure -5 is provided at the opposite end of the tube 2 and may be held in place by screws 6 or other suitable means. The pipe 1 is threaded into the closure 5 so that direct communication is provided with the interior of the tube 2. The inner surface of the tube 2 is linedwith a filter sheet 7 which is preferably made of non-combustible material, such as woven asbestos cloth. This will permit the passage of gas through the filter sheet to the interior of the tube, but will arrest smoke and soot and other solids suspended in the gas. The filter sheet 7 is held in place against the inner face of the tube 2 by a coiled wire 8 which bears outwardly against the inner face of the filter sheet. Other means may, of course, be employed for retaining the filter sheet in place, but I have found the coiled wire convenient and efiicient for this purpose.

If at any time it becomes desirable to remove the filter sheet for cleaning or replacement, this may be done by removing the screw 6 and displacing the closure 5, thus permitting access to the interior of the tube. I have found, however, that a tube of this kind lined with asbestos cloth will operate within the smoke passages of power plants for long periods of time delivering gas substantially free'fromsuspended solid material to a C0 recorder without serious clogging.

I claim 1. An intake device for gas samples comprising a tubular member having the side Wall thereof perforated, a closure for one end of said member, a removable closure for the other end of said member, a conduit communicating with the interior of said member, a cover sheet of asbestos cloth, said asbestos cloth being sufliciently porous to permit the gas sample to readily pass through without the application of pressure while preventing the entrance of solid matter and means for holding said cover sheet adjacent the inner surface of said tubular member and across the openings through the wall of said memher so that gas entering said member must pass through said cloth.

2. A sample tube for securing hot flue gases for analysis by C0 recorders or otherpurposes comprising a tubular member of sheet metal forming an intake for said gases, said tubular member havin r perforated side walls and having one end t ereot closed, a filter sheet of woven asbestos cloth positioned against the inner face of the perforated wall of said tubular member said asbestos cloth being sufiiciently porous to permit the gas sample to readily pass through without the application of pressure while preventing the entrance of solid matter, a coil of wire within said filter sheet for holding said sheet against said wall to cover the openings therethrough so that gas entering said tubular member passes through said filter sheet, a removable closure for the opposite end of said tubular member to permit access to said tubular member for cleaning or other purposes, and a conduit communicating with the interior of said tubular member.

3. Means for securing samples of gas for test purposes comprising a rigid perforated casing, an asbestos filter covering the perforations in said casing through which said gas samples are passed, said asbestos filter being sufliciently porous to permit the gas sample to readily pass through without the application of pressure while preventing the entrance of solid matter, means for holding said asbestos filter closely against said casing, and a conduit communicating with the interior of said casing for conducting gas therefrom.

4;. Means for securing samples of gas for test purposes comprising a rigid perforated outer casing, a flexible filter through which said gas samples are passed positioned within and against said outer casing, said flexible filter being sufliciently porous to permit the gas sample to readily pass through without the application of pressure while preventing the entrance of solid material, means within said casing for holding said filter against the inner face of the wall thereof, and a conduit communicating with the interior of said casing for conducting the gas therefrom.

5. Means for securing samples of gas for without the application of pressure while preventing the entrance of solid material, a spring positioned within said filter holding said filter firmly against the inner wall of said casing, and a conduit commimicating with the interior of said casing for conducting the gas therefrom.

In testimony whereof I have signed my name to this specification on this 5th day of October, A. D. 1922.

ARTHUR B. CUNNINGHAM.

test purposes comprising a shell having a Y perforated wall, woven asbestos cloth positioned within and covering the openings through said shell, said asbestos cloth being sufficiently porous to permit the gas sample to readily pass through without the application of pressure while preventing the entrance of solid material, means for holding said asbestos cloth against the inner surface of said shell, and a conduit communicating with the interior of said casing for conducting gas therefrom.

6. Means for securing samples of gas for test purposes comprising a rigid perforated outer casing, an asbestos filter through which said gas samples are passed positioned within and against said outer casin through which the gas samples are passe said asbestos filter being sufiiciently porous to permit the gas sample to readily pass through 

